Question

two solutions are prepared using the same solute

solution a: 0.27g of the solute disolves in 27.4g of t-butanol

solution b: 0.23g of the solute disolves in 24.8g of cyclohexane

which solution has the greatest freesing point change? show calculations and explain.

Answer 1

delta T = Kf*m
molality = mols/kg solvent.

I think the easy way to do this is to make up a number for the molar mass of the solute. It doesn't matter what number is used since it is the same in both solvents. I think 10 is a good number.
m for t-butanol is (0.27/10)/0.027 = 0.98 or so but you can do it more accurately.
Then m for cyclohexane is
(0.23/10)/0.0248 = 0.93 or so.
Which of those times Kf will produce the larger delta T value.If your prof is picky about significant figures you want to be careful with the explanation part and not use too many s.f.